Electromagnetically operated switch



Nov. 22, 1949 c. A. PACKARD 2,483,928

ELECTROMAGNETICALLY OPERATED SWITCH Filed Feb. 4, 1946 "I'I'I'I'Iuu'... IIIIIII'II'IIIII'I') ATTORNEVS Patented Nov. 22, 1949 ELECTROMAGNETICALLY OPERATED SWITCH Charles A. Packard, welaka, Fla., asslgnor to Struthers-Dunn', Inc., Philadelphia, Pa., a corporation of Pennsylvania Application February 4, 1946, Serial No. 645,255

'7 Claims. 1

My invention relates to electromagnetic devices and particularly to electromagnetic relays.

In accordance with one aspect of my invention, a ball of magnetic material is positioned adjacent one pole piece of an electromagnetic device by its disposition in an opening or recess in a second pole piece so located that upon energization of the device the ball is moved into engagement with and is magnetically held by both pole pieces. More particularly, the ball may be coated with material such as silver which precludes retention of the ball by residual magnetism of the pole pieces and better suits it for use as a relay contact.

Further in accordance with my invention, when the relay is de-energized, the ball may engage both the second pole piece, which serves as one contact member, and another contact member preferably having such configuration that gravity is efiective to press the ball against both of these contact members.

My invention further resides in features of construction and arrangement hereinafter described and claimed.

For an understanding of my invention and for illustration of one embodiment thereof, reference is made to the accompanying drawings, in which:

Fig. 1 is an elevational view, partly in section, showing a relay of the plug-in type;

Fig. 2 is an endview, partly in section, of Fig. 1;

Fig. 3 is a bottom view diagrammatically illus trating electrical connections of the relay element to its base terminals;

Fig. 4 is a detailed view, partly in section, illustrating significant relations of the armature and pole pieces shown in Fig. 1.

Referring to Fig. 1, the coil I is wound upon a core 2 to the upper end of which is secured as by bolt 3 a magnetic yoke member 4 having a wide portion 5 which extends downwardly toward the other end of the core 2.

The upper pole piece extension 5 to a substantial extent overlaps a second yoke member 6 which extends upwardly from below the lower end of the core 2 where it is bent laterally to form the lower pole piece 1, having therein an opening 8, preferably circular and concentric with core 2, which loosely receives the ball 9 of magnetic material. The substantial area of overlap of the extensions 5 and 6 ensures low reluctance of the gap between them in the magnetic circuit.

The yoke members 6 and S are secured in position by rivet it, which clamps the yoke member 6 to the strip of insulation H, the yoke member 4 having an opening I! which avoids electrical contact between the rivet and the yoke member 4, and by the rivets [3 which secure yoke member 4 to the strip of insulation H and which clear yoke member 6 because of openings therein provided.

The sub-assembly comprising the coil, core, and yoke members is mounted upon a base member M by the L-shaped supporting member l5 whose upstanding portion is secured as by rivets it to the lower end of the insulating strip H. The yoke 8 is provided with openings to avoid engagement of the rear heads of these rivets with the yoke member 5. Further to increase the mechanical rigidity of the assembly, the yoke member is secured to the lower end of the insulating strip by the rivet it, which as shown in Fig. 2, does not engage the support l5 because of the clearance afforded by the opening l8 in it. The support it is secured to the base 14 by a screw not shown which extends through the spacer 29 which may be molded integrally with the base.

When the coil l is de-energized, the ball armature 9 is in the lower, full-line position shown in Fig. 1. Preferably the upper face of the support is provided with a tapered opening or conical recess 28 which preferably is ofiset with respect to opening 8 so that gravity biases the ball against the pole piece i at one side or face of the opening 8. When the coil I is energized, the ball 9 is moved upwardly by magnetic attraction of the core 2 and assumes a position Fig. 4, where it engages both the core member 2 and the pole piece I, and is firmly held against both of them so long as the coil remains energized.

The spaces between pole pieces 2 and I and between pole piece I and support l5 are insufiicient to allow escape of the ball in operation of the relay or during its handling in shipment or installation.

To avoid retention, by residual magnetism, of the armature in the upper position, the ball 9 is coated with a non-magnetic material which, for use of the device as a relay, is of silver or other non-magnetic metal suited for use as an elec trical contact. Moreover, for use of the device as a relay, the lower face of the core 2 is also preferably provided with a facing 99 of silver or other suitable contact material, and likewise pole piece l also may be provided with a silver facing.

In the arrangement shown, the support 55 may be utilized as a back contact, in which event it is of metal, such as brass, preferably surfaced with silver or like contact material, the offset of the recess or opening 28 insuring adequate pressure to maintain closed a circuit including pole piece 1, ball 9 and contact ii.

In successive operations of the relay, the ball 9. at least in part due to the magnetic drag of pole piece 1, assumes many different positions so that different areas of the ball and of the stationary contacts are utilized as the actual circult-making and circuit-breaking points. Furthermore, in movement of the ball toward and from engagement with the pole pieces, there is effected a wiping action which tends to keep the contacts clean.

As apparent from the terminal connections shown in Fig. 3, by suitable choice of external connections, the relay may be utilized upon energization of coil I either to make a circuit, to break a circuit, or to make one circuit and break another. To facilitate installation and replacement of the relay, the terminals 20, 2!, 22, 23 and 24 are molded in and extend from the base member ll of the relay for reception by socket terminals.

The base I4 is provided with a recess 25 into which the lugs 26 of a metal cover or shield 21 may be inturned to hold it imposition. In external appearance and size, the relay resembles a small radio tube of th metal type and like a tube may be' plugged into a socket for readily detachable connection to all the controlled and controlling circuits.

It is to be understood my invention is not limited to the preferred embodiment shown but is co-extensive in scope with the'appended claims: for example, instead of providing an offset recess 28 in the lower contact to force the ball, when released from pole piece 2, against the pole piece I, the upper surface of contact [5 may be provided with a raised portion suitably offset with respect to the center of hole 8 in pole piece 1.

What I claim is:

1. An electromagnetic device comprising a ball 01' magnetic material, an upper pole piece, a lower pol piece apertured to loosely receive the ball when in gravity-biased position, a contact member below said lower pole piece and having a recess positioned to insure engagement of the ball with said lower pole piece when in said position, and a coil effective upon energizetion to lift the ball from said position and to effect its engagement with both of said pole pieces.

2. An electromagnetic device comprising a core of magnetic material, a coil thereon, a magnetic member connected to the upper end of said core and extending downwardly toward the lower end thereof, a second magnetic member spaced from the lower end of said core and extending upwardly closely adjacent said first member to provide by their overlapping portions a gap having low magnetic reluctance, a contact below said second member and having an upwardly extending portion, a ball armature for engaging said second magnetic member or said contact member and said second magnetic member, and'means for mechanically supporting said magnetic members and said contact comprising an insulating member to which the downwardly extending portion of the first magnetic member and the upwardly extendin portion of the second magnetic member and of said contact are individually secured.

3. An electromagnetic device comprising a ball of magnetic material, an upper pole piece, a lower pole piece apertured loosely to receive the ball when in gravity-biased position, a contact member below said lower pole piece and having configuration forcing the ball when in said position against the lower pole piece, and a coil effective upon energization to cause by the combined action of the pole pieces a lifting and turning of the ball and its ultimate engagement with both of said pole pieces.

4. An electromagnetic device comprising a core of magnetic material, a ball armature, a magnetic member connected to the upper end of said core and extending downwardly toward the lower end thereof, a second magnetic member having one portion apertured to loosely receive said ball armature in position below said lower end of said core and having another portion extending upwardly closely adjacent said first member to provide by their overlapping portions 8. gap having relatively low magnetic reluctance, a contact below said second member having such configuration that said ball armature is forced into engagement with said second ember and having an upwardly extending portlon, means for mechanically supporting said magnetic members and said contact comprising an insulating member to which the downwardly extending portion of the first magnetic member and the upwardly extending portions of said contact and said second magnetic member are individually secured, and a coil effective upon cncrgization to move said armature from position of engagement with said contact and said second magnetic member to position of engagement with said second magnetic member and said core.

5. An electromagnetic relay comprising a core of magnetic material, a coil thereon, a stationary magnetic member attached to one end of said core and having an integral portion extending parallel to said core toward the other end thereof, 'a second stationary magnetic member having one portion extending over and spaced a fixed distance from said other end of said core and a second integral portion extending toward said first end of the core parallel to and in spaced overlapping relation to aforesaid portion of said first-named member to afford between the overlapping portions of said members a flux path of relatively low magnetic reluctance, and means including insulation between said overlapping portions for supporting said members in electric isolation from each other for utilization as contact elements of the relay.

6. An electromagnetic relay comprising a core of magnetic material, a coil thereon, a magnetic member attached to one end of said core and having a portion extending toward the other end thereof, a second magnetic member extending over and spaced from the other end of said core and having a portion extending toward said first end of the core and substantially overlapping said portion of the first-named magnetic member to afford between said overlapping portions of said members a gap of relatively low magnetic reluctance, insulation means between said overlapping portions for holding said members and core in fixed relative positions with electric isolation of said second member from said core and first member, and a ball armature serving as a movable contact of said relay movable upon energization of said coil to engage said core and said second member which serve as fixed contacts of said relay.

7. An electromagnetic relay comprising a core of magnetic material, a coil thereon, a magnetic member attached to the upper end of said core having a portion extending downwardly toward the lower end thereof, a second magnetic member extending over and spaced from the lower end of said core and having a portion extending upwardly closely adjacent said portion of said first member in substantially overlapping relation therewith to provide by their overlapping portions a gap of relatively low magnetic reluctance, means for supporting said coil, core and members in fixed relative position comprising an insulating member to which said overlapping portions of said members are individually secured in electrical isolation for utilization of said core and members as stationary electrical circuit elements of said relay, and movable contact structure actuated in response to energlzation of said coil for electrical engagement with said core and said second magnetic member.

CHARLES A. PACKARD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED s'rA'rEs PATENTS Number Number 

